The objective of this study is to analyze, in detail, the patterns of denervation produced by certain neurotoxic substances. Initially experimental acrylamide neuropathy in the cat will be studied. Electrophysiological recordings will be made from single units isolated in dorsal root filaments which originate in skin and muscle receptors. The findings from single unit studies will be correlated with clinical and histological observations. We plan to document whether nerve fiber function fails first in the nerve terminals as suggested by the dying-back hypothesis and whether nerve fibers of specific size or function are differentially involved. Information of this kind will contribute towards an understanding of the basic biochemical derangement produced by these nerve toxins, and ultimately enlarge understanding of analogous human neuropathies.